Precise and positioned fixing of semiconductor substrates is essential for a host of processes in the semiconductor industry. To handle these semiconductor substrates, the generally very thin and susceptible semiconductor substrates are placed on a workholding fixture, a so-called chuck, and fixed there. The technologies known for fixing semiconductor substrates on chucks cannot be used especially for extremely thin semiconductor substrates with a thickness of less than 100 microns, especially less than 50 μm, and for substrates with a topography.
One very frequently used type of fixing takes place using a vacuum or negative pressure, a flat semiconductor substrate being fixed on a flat hardened surface into which vacuum paths are milled. For especially thin semiconductor substrates the semiconductor substrates can break or can at least be damaged along the vacuum paths.
A still greater problem is the fixing of substrates with very high topography, the topography being produced for example by so-called bumps. Bumps are spherically, conically or prismatically (cuboidally) applied conductive materials which are used later for making electrical contact with other components. The bumps can have a height of more than 500 μm, typically between 4-200 μm, generally between 10-150 μm, and can be distributed in a large plurality over the entire substrate surface. It follows from this that fixing of the semiconductor substrate is not sufficiently possible with the known methods.
Another possibility consists in electrostatic fixing. Electrostatic fixing devices however have the disadvantage that damage to the complex circuits on the semiconductor substrate is probable due to build-up of electrical fields.
Therefore the object of this invention is to devise a workholding fixture with which thin semiconductor substrates and semiconductor substrates with topography can be reliably and carefully held and fixed.